It is known to package semiconductor optical emitter and receiver devices in a single housing or package for use, among other things, as a combined transmitter-receiver. In a typical application, the emitter is a light emitting semiconductor diode (LED) which emits light when energized. The light from the LED travels through the transparent cover and exits the device package where it may encounter a separate receiver device or an object that returns part of the emitted light back through the transparent cover to the receiver device in the same housing. Phototransistors, photodiodes and photoresistors are well known receiver devices. It is important that the wavelength sensitivity of the receiver device be such that it can reasonably detect the light wavelength emitted by the LED or other optical emitter within the housing. Various electro-optic emitter-receivers are described in Okabe U.S. Pat. No. 4,309,605, Mikami et al. U.S. Pat. No. 4,614,958, and Inaba et al. U.S. Pat. No. 4,521,681, which are incorporated herein by reference.
Prior art devices suffer from a number of disadvantages, such as for example, use of complex and expensive semiconductor devices and/or housings which increase manufacturing cost and/or fail to provide the desired performance.
Accordingly, there is an ongoing need for improved single package, semiconductor emitter-receiver devices, and it is an object of the present invention to provide such.
It is a further object of the present invention to provide an improved single package, semiconductor emitter-receiver device wherein the emitter and receiver are both outward facing and adapted to be mounted on a simple lead frame well suited for automated assembly and low cost.